Field of the Invention
The present invention relates to asparaginase variants, polynucleotides encoding the variants, methods of producing the variants, and methods of using the variants. The present invention further relates to processes of producing sugars, dextrins and fermentation products from plant material using one or more fermenting organisms.
Description of the Related Art
It is well known that acrylamide formation in heated food products may be reduced by a treatment reducing the amount of asparagine in the food materials, such as by subjecting the food materials to the action of the enzyme asparaginase (see e.g. WO2004/026042).
A number of fungal asparaginases have been identified; see e.g. WO2004/030468 or WO2004/032648. Protein engineering of such asparaginases to improve their properties has been described. WO2008/128974, WO2008/128975 and WO2011/134916 disclose variants of asparaginase from A. niger having an improved activity at more alkaline pH. WO2008/110513 discloses variants of asparaginase from A. oryzae having an improved thermostability. However, in certain industrial applications of asparaginase, e.g., in the production of French fries, an even higher thermostability is desired.
It is an object of the present invention to provide asparaginase variants with improved properties compared to its parent.
A vast number of commercial products that are difficult to produce synthetically are today produced by fermenting organisms. Such products include alcohols (e.g., butanol, ethanol, methanol, 1,3-propanediol); organic acids (e.g., acetic acid, citric acid, gluconate, gluconic acid, itaconic acid, lactic acid, succinic acid, 2,5-diketo-D-gluconic acid); ketones (e.g., acetone); amino acids (e.g., glutamic acid); gases (e.g., H2 and CO2), and more complex compounds, including, for example, antibiotics (e.g., penicillin and tetracycline); enzymes; vitamins (e.g., riboflavin, B12, beta-carotene); and hormones. Fermentation is also commonly used in the consumable alcohol (e.g., beer and wine), dairy (e.g., in the production of yogurt and cheese), leather, and tobacco industries.
A vast number of processes of producing fermentation products, such as ethanol, by fermentation of sugars provided by degradation of starch-containing materials are known in the art.
However, production of, sugars, dextrins and fermentation products, such as ethanol, from such plant materials is still too costly. Therefore, there is a need for providing processes that can increase the yield of the fermentation product and thereby reduce the production costs.
It is a further object of the present invention to provide an improved process for producing a fermentation product.